This specification refers to integrated semiconductor devices, in one embodiment to lateral power integrated semiconductor devices and a manufacturing method therefor.
Many functions of modern devices in automotive, consumer and industrial applications such as driving a motor or an electric machine are controlled by Electronic Control Units (ECUs). In automobiles, for example, igniting an airbag, switching the valves of an ABS on and off, and injecting fuel into the cylinders of the motor are activated and regulated, respectively, by different decentralized ECUs. Even many home appliances like a washing machine and a dish washer are controlled by ECUs. Typically, an ECU includes analog, digital and power modules and at least one microcontroller (μC). To minimize cost, size and weight of the electronics, the digital and analog circuits of an ECU are typically monolithically integrated on a common substrate as a single integrated circuit (IC). Depending on application, this can e.g., be achieved in a HV-CMOS technology or in a smart power technology. While HV-CMOS technology combines high-voltage MOS (HV-MOS) and CMOS transistors, smart power technology offers in addition bipolar transistors for high precision analog functions, and DMOS transistors to drive loads up to several amperes.
ESD pulses (ESD=electrostatic discharge) occurring during assembly and energetic electric pulses during operation, e.g., due to switching of actuators, should not lead to malfunction or destruction of an ECU. Even simple actuators such as a contact bouncing relay generate repeating over-voltage pulses with fast rise and fall times. With inductive loads, negative voltages may occur during reverse currents as well. Energetic electric pulses typically last a few nanoseconds up to several milliseconds. Many of these pulses have been standardized in the ISO-7637. Some of these pulses which are in the range of nanoseconds are similar to ESD pulses. Even if the pulses do not destroy the other modules, such pulses may induce noise into the substrate (“substrate potential fluctuations”) and hence function as a noise source for the other modules. This may result in a shift of the operating point or a complete intermittent fault of these modules during operation. For example, negative voltage pulses injected into a motor driver module, in particular for drive loads in the ampere range, may provide a significant noise source for an analog measuring module and/or a logic module and/or a further driver module.
For these and other reasons there is a need for the present invention.